N-Aralkylpolyamine complexes-X some complexes of copper(II) and nickel(II) with a variety of polyamine ligands

Abstract Ten new complexes are reported: Cu(MBEn) 2 (NO 2 ) 2 , Cu(DBEn) 2 (NO 2 ) 2 ·3H 2 O, Cu(DBEn) 2 (NO 2 ) 2 ·H 2 O, CuMe 4 En(NO 2 ) 2 , CuEt 4 En(NO 2 ) 2 , CuMe 2 DBEn(NO 2 ) 2 , Ni(MBEn) 2 (NO 2 ) 2 , Ni(DBEn) 2 (NO 2 ) 2 , NiEt 4 En(NO 2 ) 2 and NiMe 2 DBEn(NO 2 ) 2 (MBEn = N-benzylethylenediamine; DBEn = N,N′-dibenzylethylenediamine; Me 2 DBEn = N,N′-dimethyl-N,N′-dibenzylethylenediamine; Me 4 En = N,N,N′,N′-tetramethylethylenediamine: Et 4 En = N,N,N′,N′-tetraethylethylenediamine.) All are magnetically normal high-spin complexes. The nitrite groups are chelated, asymmetrically in copper and symmetrically in the nickel complexes of Me 4 En, Et 4 En and Me 2 DBEn. Ni(DBEn) 2 (NO 2 ) 2 , a nitrito complex in the solid phase, exists in a nitro-nitrito equilibrium in chloroform. The solid trihydrate nitrito complex, Cu(DBEn) 2 (ONO) 2 ·3H 2 O on heating at 110°C gave Cu(DBEn) 2 (NO 2 ) 2 ·H 2 O, a nitro-nitrito isomeric mixture. The nitrite groups are coordinated through N in Mi(MBEn) 2 (NO 2 ) 2 and O in Cu(MBEn) 2 (ONO) 2 . It is suggested that steric factors as well as the nature of the metal ion play an important part in the mode of nitrite coordination.